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Billing Models for Peer-to-Peer Electricity Trading Markets with Imperfect Bid-Offer Fulfillment
No full textThis paper proposes four new billing models for peerto-peer electricity trading markets that take into account electricity volume deviations of market participants from their bids and volumes. These billing models incorporate different cost sharing mechanisms so that (i) the costs incurred due to these deviations are minimal for consumers and prosumers and (ii) include non peer-to-peer participants as well. The former is achieved by designing cost sharing mechanisms which split the cost socially, while the latter is achieved by introducing a mid market that clears all the available supply from the P2P market. Through simulations of a small-scale community, we have demonstrated the effectiveness of our billing models in significantly increasing prosumers’ rewards and reducing consumers’ bills.<br/
Pore-scale Large Eddy Simulation of Turbulent Flow and Heat Transfer over Porous Media
No full textThis paper investigates turbulent fluid flow and heat transfer over a porous medium in a channel using pore-scale large eddy simulation. Special attention is placed on the exchange of heat and flow between the porous and non-porous regions through the interface between the two regions. For this purpose, two different porous systems made of a packed bed of spheres and rectangular rods are analysed and the results are compared against a solid block case of the same size. Flow visualization shows that a significant portion of the fluid entering the porous blocks leaks from the porous region to the non-porous region through the porous-fluid interface. To discuss the effects of this flow leakage on the flow features and heat transfer, discussions are made regarding velocity, pressure, and temperature fields, as well as coherent structures, and turbulence production. The flow pattern inside the porous region indicates that the flow leakage clogs the pore channels inside the porous medium which induces a significant reduction in the streamwise momentum of the pore flow. In addition, coherent structures show that flow leakage leads to the creation of counter-rotating vortex pairs of fluid flow within and above the porous block that results in the formation of organized hairpin structures. Finally, the comparison of turbulence production for the porous and solid cases together with the onset growth of the Kelvin-Helmholtz instability on the porous-fluid interface show a reduction in turbulent kinetic energy above the leading edge of porous blocks. This observation implies that for the porous cases the transition to turbulence is postponed to the downstream of the porous block and it is not achieved as fast as the solid block
Randomized, Phase II Study of Selumetinib, an oral inhibitor of MEK, in combination with cisplatin and gemcitabine chemotherapy for patients with advanced biliary tract cancer.
No full textIntroductionCisplatin and gemcitabine (CisGem) is standard chemotherapy for advanced biliary tract cancer (BTC). The MEK inhibitor selumetinib showed synergy with gemcitabine when administered sequentially in BTC. This randomized phase 2 trial aimed to assess the efficacy of sequential or continuous selumetinib with CisGem.MethodsPatients with advanced BTC received CisGem; arm A included selumetinib every day, arm B: selumetinib, days 1-5, 8-19 each cycle. Arm C received CisGem alone. Selumetinib was dosed at 75mg BID but amended to 50mg BID due to toxicity. Results51 participants were evaluable for response. No significant difference was seen in mean change in tumor size at 10 weeks between Arm A and C (-7.8% vs -12.8%, p=0.54) or arm B and C (-15% vs -12.8%, p=0.78). There was no difference in median progression-free survival (6.0, 7.0, 6.3 months, p>0.95) or overall survival (11.7, 11.7, 12.8 months, p=0.70) for arms A, B and C, respectively. More participants experienced grade 3-4 toxicities in selumetinib-containing arms. More participants in arm A required chemotherapy dose reductions (p=0.01) with lower chemotherapy dose intensity during the first 10 weeks.ConclusionAdding sequential or continuous selumetinib to CisGem failed to improve efficacy and increased toxicity in patients with advanced BTC
Bounds for the chi-square approximation of Friedman’s statistic by Stein’s method
No full textFriedman’s chi-square test is a non-parametric statistical test for r treatments across n trials to assess the null hypothesis that there is no treatment effect. We use Stein’s method with an exchangeable pair coupling to derive a bound on the distance between the distribution of Friedman’s statistic and its limiting chi-square distribution, measured using smooth test functions. Our bound is of the optimal order n−1, and also has an optimal dependence on the parameter r, in that the bound tends to zero if and only if r/n→0. From this bound, we deduce a Kolmogorov distance bound that decays to zero under the weaker condition r1/2/n→0
Combining sparse approximate factorizations with mixed precision iterative refinement
No full textThe standard LU factorization-based solution process for linear systems can be enhanced in speed or accuracy by employing mixed precision iterative refinement. Most recent work has focused on dense systems. We investigate the potential of mixed precision iterative refinement to enhance methods for sparse systems based on approximate sparse factorizations. In doing so we first develop a new error analysis for LU- and GMRES-based iterative refinement under a general model of LU factorization that accounts for the approximation methods typically used by modern sparse solvers, such as low-rank approximations or relaxed pivoting strategies. We then provide a detailed performance analysis of both the execution time and memory consumption of different algorithms, based on a selected set of iterative refinement variants and approximate sparse factorizations. Our performance study uses the multifrontal solver MUMPS, which can exploit block low-rank (BLR) factorization and static pivoting. We evaluate the performance of the algorithms on large, sparse problems coming from a variety of real-life and industrial applications showing that the proposed approach can lead to considerable reductions of both the time and memory consumption
The reporting and methodological quality of split-mouth trials in oral implantology: A methodological study
No full textObjectives: To assess the reporting and methodological quality of split-mouth trials (SMTs) in oral implantology published during the past ten years, and to investigate whether there was any improvement over time.Materials and Methods: We searched PubMed for SMTs in oral implantology published during 2011-20. We used CONSORT 2010, its extension for within-person trial (WPT), and an SMT-specific methodological checklist to assess trial reporting quality (TRQ), WPT-specific reporting quality (WRQ), and SMT-specific methodological quality (SMQ), respectively. Binary scores were given to each item, and total scores of TRQ (range 0-32), WRQ (0-15), and SMQ (0-3) were calculated for each study. Multivariable regression analyses were performed to compare the quality of SMTs published before (2011-17) and after (2018-20) the release of CONSORT for WPT.Results: Seventy-nine SMTs were included. The mean TRQ, WRQ, and SMQ were 16.4, 6.7, and 1.3, respectively. Less than one-third (n=25, 31.6%) reported the rationale for using splitmouth designs. Only 4 (5.1%) trials adequately conducted sample size calculation, and 40 (50.6%) used appropriate statistical methods that considered dependency and clustering of data. In multivariable analyses, compared with 2011-17, studies published in 2018-20 had significantly higher TRQ (P = 0.044), while WRQ and SMQ did not show improvement.Conclusions: The reporting and methodological quality of SMTs in oral implantology need to be improved. Joint efforts are needed to improve the reporting and methodology of SMTs in this field
The Cold Futures of Mouse Genetics: Modes of Strain Cryopreservation since the 1970s
No full textCryopreservation, or the freezing of embryos or sperm, has become a routine part of many research projects involving laboratory mice. In this article, we combine historical and sociological methods to produce a cryopolitical analysis of this less explored aspect of animal research. We provide a longitudinal account of mouse embryo and semen storage and uses in the UK and show that cryopreservation enabled researchers to overcome particular challenges—fears of strain loss, societal disapproval, and genetic drift—in ways which enabled the continued existence of strains and contributed to the scaling up of mouse research since World War II. We use the theoretical lens of cryopolitics to explore three different, yet overlapping, cryopolitical strategies that we identify. All share the ability to ensure the continued maintenance of genetically-defined strains without the need for continually breeding colonies of mice. We argue that, in contrast to more common imaginaries of species conservation, the cryopolitical rationale can best be understood as purposefully not letting the strain die without requiring animals to live. The ability to freeze mice, then, had the potential to unsettle who the objects of care are in mouse research, from individual animals to the concept of the strain itself
Educational psychologists’ use of cognitive behavioural therapy in professional practice
No full textAim: There is increasing recognition of the centrality schools have in supporting children and young people’s mental health and wellbeing, and the role of educational psychologists (EPs) in supporting this. Cognitive behavioural therapy (CBT) is a frequently-used, evidence-based approach for supporting a range of outcomes. The purpose of this study is to explore how EPs are operationalising CBT in their practice, and which therapeutic competencies are demonstrated. Method: Semi-structured interviews were completed with a self-selecting sample of eight EPs reporting to be knowledgeable about CBT and to regularly use it in their practice. Transcribed data were analysed using inductive and deductive thematic analysis. Findings: Key themes related to CBT in applied practice, the EP role, drawing on other psychological approaches, ethical practice, external influences and having a holistic view of the child. EPs were using CBT across a continuum of formality in therapeutic work and multi-faceted casework. A range of CBT competencies was demonstrated in practice with children and young people, and adults. Limitations: As an exploratory research study the sample size was very small. The self-selecting sample does not claim to be representative of the wider EP population. The extent to which findings enable an understanding of the effectiveness of CBT within wider EP practice is extremely limited. Conclusions: The flexibility of CBT as a therapeutic modality gives insight into its potential wider contribution across EP practice. Potential implications for EP professional training and practice are considered
